The invention relates to a method and apparatus for storing, searching and playing back audiovisual information and data files. In particular, the invention relates to a multi-media memory device.
Storing and playing back items of multimedia information (video, audio, data, control information) on digital storage media (e.g., CD-ROM, optically writable hard disk, magnetic hard disk) is one of the most important functions in multimedia systems.
Although the capacity to store items of information on digital storage media is constantly growing, the large amount of data of multimedia information continues to present a massive storage problem.
A standardized method under ISO/IEC 11172 (also known as MPEG-1) enables storage of approximately one hour of audiovisual information on CD-ROM with data streams of 1.5 Mbits/s. Other, non-standardized audiovisual compression methods commonly used in PC applications also enable approximately one hour of stored audiovisual program, albeit with a worse image and tone quality.
In relation to these known methods characterized in Table 1 below, an arrangement according to the present invention enables considerably higher compression, more effective multiplexing, and more effective controlling of multimedia data streams.
TABLE 1 Examples of playback time for multimedia memory solutions based on ITU H.324 Playback time Playback time Playback time at 32 kbit/s at 128 kbit/s at 512 kbit/s QCIF CIF ITU-R 601 (180 .times. 144) (360 .times. 288) (720 .times. 576) Image Image Image resolution at resolution at resolution at Memory H.263; G.723; H.263; H.263; Volume G4kbit/s G.723; G.728; G.728, G.729; Medium: (MByte): audio G.729 audio G.722 audio Diskette: 1.4 About 6 -- -- minutes CD-ROM 660 about 46 about 11 about 2.5 hours hours hours Example 10 about 41 about 10 -- Data minutes minutes File: Hard -- about 240 about 1 about 4 Disk/ kbyte/min. Mbyte/min mbte/min Minute Example 540 about 38 about 9 hours about 2.25 Hard hours hours Disk:
The quality of MPEG-1 Video and MPEG-1 Audio is indeed as a rule better than the other methods listed in Table 1, but there are numerous applications in which a reduced video and audio quality is completely sufficient (e.g. multimedia mail, video images with head and shoulders, multimedia lexicons).